Lubrication and cooling system for connecting rod and piston

ABSTRACT

A lubricating and cooling system for lubricating a connecting rod and cooling the underside of a piston of an internal combustion engine.

United States Patent 1191 Patchen Jan. 15, 1974 [54] LUBRICATION ANDCOOLING SYSTEM 2,899,016 8/1959 Swayze 184/65 FOR CONNECTING O ANDPISTON 3,495,685 2/1970 Rinsum 184/6.5 2,991,769 7/1961 Chapin 92/157 XInventor: Paul .L-Patchen, ChICflgO, 111. 3,555,972 1/1971 Hulsing..92/157 2,192,782 3/1940 Westfield.. 184/65 [73] Assgnee' l 1,948,340 21934 D0123 et a1 184/65 Milwaukee, WIS. [22] Filed: y 197-2 FOREIGNPATENTS OR APPLICATIONS 1,025,674 3/1958 Germany 184/65 [21] Appl. No.2252,366

Primary Examiner-Manuel A. Antonakas [52] 1.1.8. CI 184/65, 92/157,308/78 AttrneyArthur L. Nelson et a1. [51] Int. Cl. Flllm 1/06 [58]Field of Search 92/157; 184/65, 7 ABS RA T A lubricating and coolingsystem for lubricating a con- 5 References Cited necting rod and coolingthe underside of a piston of an UNITED STATES PATENTS internalcombustion engine. 2,449,657 9/1948 Kishline 92/157 16 Claims, 10Drawing Figures J41 dig 19 2a lag/7% A?! 7 16 .15

12 91 M l, [II \L 2* 11 3 7/ -Z9 {g p a! LUBRICATION AND COOLING SYSTEMFOR CONNECTING ROD AND PISTON This invention relates to internalcombustion engines and more particularly to a lubrication and coolingsystem forlubricating the crankshaft bearings and wrist pin bearings andcooling the underside of a piston.

The reciprocating internal combustion engine has used various types oflubricating systems for lubricating the bearings of the crankshaft andthe wrist pin bearing. Forced lubricating systems generally include adrilled crankshaft with a drilled connecting rod usually drilled on theaxial center of the rod to convey lubricating oil from the crankshaft tothe wrist pin bearing. The main bearings, the crankpin bearings, and thewrist pin bearings generally define oil grooves for improving thelubrication characteristics of the bearing per se as well as.transmission of lubricating and cooling oil through the connecting rodfor cooling the underside of the piston. The disadvantage of theconventional method of piston cooling is in its characteristic oildelivery curve. Maximum oil flow is achieved at its lowest operatingspeed and diminishes as the speed increases thereby providing a negativeslope for the oil delivery engine speed curve. This establishes a needfor an exceedingly large oil pump capacity to maintain oil pressure atlow speeds and yet rarely provides the desired flow rate for pistoncooling at full load speeds. This is particularly true in the engines ofhigher speed operation. Accordingly, it is desirable to improvethe flowcharacteristics of the lubricating oil with the engine speed to providethe necessary oilpressure for lubrication of the bear ings as well aspiston cooling. This can be accomplished by providing a single oilsupply hole in the crankpin bearing in conjunction with -a partiallygrooved bearing shell to function as a rotary valve. Through properorientation communication is provided when positive flow conditionsexist and communication is terminated when the negative flow conditionsexist to increase the net flow at full load speed. This same arrangementprovides communication one-half or less of the time reducing deliveryunder conditions when negative flow conditions do not appear in theoperating cycle to decrease the flow rate at low idle speeds. Thus, flowis increased at full load speed and reduced at low idle speed, over thatproduced by the natural delivery curve, when communication iscontinuous, to provide a positive slope of the delivery curve. Morespecifically, this lubricating and cooling system provides asymmetricaltiming. This provides a minimum communication period or duration of flowrate in degrees of crank rotation for a given flow rate at full loadspeed. Likewise, this minimum communication period provides a maximumpositive slope or reduction in flow rate as the engine speed is reducedto low idle.

More specifically, lubrication oil flow is produced by main oil gallerypressure, pressure due to crankshaft rotation, and alternating positiveand negative pressure due to connecting rod reciprocation. At low idlespeed the net pressure producing flow is the summation of the positivemain oil gallery pressure and the positive crankshaft produced pressurein conjunction with a weak fluctuating positive and negative pressureproduced by connecting rod reciprocation. Under these conditions apositive pressure persists and the flow is continuous resulting in highflow rate if uncontrolled.

At full load speed the net pressure producing flow is a summation of-the increased positive main gallery pressure, increased crankshaftrotation producing pressure and a strong fluctuating positive andnegative pressure produced by connecting rod reciprocation. Under theseconditions both positive and negative net pressure periods exist whichdiminish the positive flow rate. This is due to the fact that net flowis the algebraic sum of positive and negative flow periods of a cycleand the negative flow subtracts from the positive flow resulting in thedecreased net delivery. Through careful selection of timing to providethe required flow rate at full load speed with minimum duration, maximumpositive slope of the delivery curve is attained to provide minimum flowrate at low idle speed.

Accordingly, this invention provides asymmetrical timing of essentiallya rotary valve in any bearing between the main oil gallery pressure atthe main bearing and a lubrication oil spray on the underside of thepiston to provide a positive'fl'ow rate with increase in engine speed.

It is an object of this invention to provide a lubricating and coolingsystem for an internal combustion engine having a drilled hole in thecrankshaft and a bearing shell groove in communication with each otherprimarily during the down stroke of the connecting rod.

It is another object of this invention to provide asymmetrical timingfor oil flow through the connecting rod to provide increased flow ofcooling oil as the engine speed increases.

It is a further object of this invention to provide initiation ofcommunication between the main bearing and the cooling jet of theconnecting rod within a range of approximately 45 before top dead centerand for maintaining communication for the range of approximately and ofcrankshaft rotation through a rotary valve means.

It is a further object of this invention to provide maximum loadcarrying capacity for the crankpin bearing by eliminating theinterruption of the bearing surface caused by the conventional oilgroove on the major thrust portion of the main bearing or crankpinbearing of the crankshaft.

The objects of this invention are accomplished by providing a mainbearing journal on the crankshaft with an oil groove for at least aportion of the periphery of the journaled portion of the crankshaft. Anoil passage is formed in the crankshaft between the journaled portion onthe main bearing and a journaled portion on the crankpin to supply oilto an oil groove formed in the crankpin end of the connecting rod. Theoil groove on the crankpin portion of the connecting rod intermittentlycontrols communication" between the main oil gallery pressure and an oilpassage transmitting oil to the wrist pin bearing for spraying theunderside of the piston. Asymmetrical timing of a valve means controlsthe flow of oil for cooling the underside of the piston during theperiod of time the inertia forces of the oil column aid in increasingthe oil pressure at the wrist pin bearing and terminate communicationwhen the inertia forces in the oil passage of the connecting rod opposethe main gallery oil pressure to thereby provide a positive oil deliveryflow with increase in engine speed.

Referring to the drawings, FIG. 1 illustrates a cross section view of anin-line engine having a bearing split on the crankpin bearing normal tothe axis of the connecting rod.

FIG. 2 illustrates a cross section view of the right bank of a V-enginehaving lubrication passage opening at 40 before top dead center with a180 oil groove in the crankpin bearing.

FIG. 3 illustrates the right bank connecting rod as shown in FIG. 2 atthe termination of communication of the lubrication oil passages in thecrankpin bearing.

FIG. 4 illustrates the left bank of a V-engine with lubrication passageopening at 40 before top dead center and 180 lubrication groove in thecrankpin bearing.

FIG. 5 is a view similar to FIG. 4 with the crankshaft rotated toterminate communication of the lubrication oil passages.

FIG. 6 is a graph illustrating oil flow in gallons per minute as relatedto engine speed in revolutions per minute with oil passage opening at 30before top dead center, and an oil groove in the crankpin bearing oflengths 90, 120 and 150.

FIG. 7 is a graph illustrating oil flow in gallons per minute withrelation to engine speed in revolutions per minute with lubrication oilpassage opening at 45 before top dead center and oil grooves in thecrankpin bearing with lengths of 90, 120 and 150.

FIG. 8 illustrates a graph showing oil flow in gallons per mintue withrelation to engine speed in revolutions per minute with lubricationpassage opening at 60 before top dead center and oil groove lengths of90, 120 and 150 in the crankpin bearing.

FIG. 9 is a fragmentary side view of the crankshaft showing lubricationoil passages from the journaled portion in the main bearing to thejournaled portion in the crankpin bearing and the planes of the viewsshown in FIG. 2 and 3 as well as FIGS. 4 and 5 for the right and leftbanks of the V-engine.

FIG. 10 is a graph illustrating oil flow in gallons per minute ofconventional engines with continuous communication in the lubricatingoil passages from the main gallery pressure at the main bearing to thejet spraying the underside of the piston as contrasted to the oil flowfor a system as covered by this invention.

Referring to the drawings, FIG. 1 illustrates an in-line engine. Theengine includes a head 1 supporting a fuel injector 2 for injection offuel into the combustion chamber 3. The engine block'4 receives a sleeveliner 5. The piston 6 reciprocates within the liner 5 when the engine isin operation.

The piston 6 is connected by a wrist pin 7 to the connecting rod 8. Theconnecting rod 8 contains a bushing 9 forming an annular oil groove 10on its inner periphery. The oil groove 10 is connected through the bore11 to the spray orifice 12 for spraying the underside of the piston 6. I

A connecting rod 8 forms a diagonal passage 13 extending through theshank of the connecting rod and through a portion of the bushing 9 toprovide communication to the annular groove 10. The crankpin bearing 119of the connecting rod 8 forms a bearing split which is normal to thelongitudinal axis of the connecting rod. The rod end of the crankpinbearing receives a bearing shell l4 while the cap end 15 receives abearing shell 16. The cap end 15 is connected to the rod end 17 by meansof a plurality of bolts 18.

The crankpin 19 of the connecting rod 8 is received within the bearingshells l4 and 16. For the purpose of illustration, the bearing shells'l4 and 16 are interchangeable and form a total lubrication groove of 90in the crankpin bearing 119. Accordingly, each bearing shell has agroove extending for 45 which are in communication with each other.

The groove 21 is in continuous communication with the lubrication oilpassage 13 and intermittently in communication with the passage 22 whichis formed in the crankarm of the crankshaft 20 and extends from the mainbearing 26 to the crankpin bearing 119.

It is understood that the crankpin bearing groove 21 might be extendedto include an arc of as shown by the groove extension 23 in the bearingshell 14 and the groove extension 24 in the bearing shell 16 shown inphantom. Likewise, the passage 22 may be used in combination with oilgroove 21 to initiate communication in the passages transmittinglubricating oil at an earlier point in time; in other words, 45 earlier.Likewise, a phantom passage as shown by passage 25 in the crankshaft maybe used which would initiate communication between the passage 13 andthe crankshaft passage 25 at top dead center and continue communication180.

Accordingly, it is understood that initiation or termination ofcommunication between the main bearing and the spray orifice 12 iscontrolled by suitable drilling of the crankshaft together with oilgrooves cut in the bearing shells l4 and 16. Initiation of the timing ofthis initial communication can be varied by any point of crankshaftrotation, and the duration of the communication may also be controlledto any length of time so desired to provide the desired oil flow ratewith response to engine speed.

The main bearing 26 includes the upper and lower sections of the bearingshells 28 and 29 respectively. For the purpose of illustration, the mainbearing 26 as shown in FIG. 1 has a peripheral groove 30 for a full 360.The oil passage 22 in the crankshaft is in communication with the oilgroove 30 continuously and intermittently in communication with the oilgroove 21 of the crankpin bearing 119 as the crankshaft rotates.

A lubrication oil pump 31 operates in response to engine rotation andreceives oil from oil reservoir 32. The engine lubricating and coolingoil is returned to the reservoir 32 as it is circulated through thelubrication and cooling system.

Referring to FIGS. 2 and 3, the right bank of the V- engine crankshaftand connecting rod is shown. It is assumed that a cooling andlubricating construction as shown in FIG. 1 may be used in connectionwith the V- engine components shown in FIGS. 2 and 3. It is understoodthat the right bank of cylinders of the V-engine is on the righthandside of the engine and facing forwardly, and accordingly, the section asshown in FIGS. 2 and 3 are looking rearwardly. The right bank is shownat a 45 angle to a vertical in FIGS. 2 and 3. Accordingly, the left bankof the V-engine is shown at 45 to a vertical in FIGS. 4 and 5 since theV-angle of the engine described is a 90 V.

The crankshaft 34 includes a main bearing 35 including upper shell 36and lower shell 37. The journaled portion 38 of the crankshaft 34 has across passage 39 drilled diametrically through the crankshaft. The upperbearing shell 36 defines a 180 oil groove 40 and with the cross drilleddiametrical passage 39, the oil groove 40 is in continuous communicationwith the passage 39. The cross passage 39 and oil groove 40 areconnected to a suitable lubrication pump driven by the engine whichprovides the main oil gallery pressure.

The connecting rod 41 has a diagonal split 42 at 45 to the longitudinalaxis of the connecting rod 41. With the connecting rod 41 having adiagonal split 42 at 45 and the right bank of the V-engine on a 90 V,the bolts 43 and 44 can be conveniently removed from the underside ofthe engine, if necessary, for repair.

The crankpin 45 is connected through the crankarm 46 to the journaledportion 38 of the crankshaft in the main bearing.

The groove 40 in. the bearing shell 36 is in constant communication withthe lubrication oil passage 39 which is connected to the passage 47through opening 51 in the crankarm 46. The passage 47 is also connectedto a passage 48. The passage 48 is in communication with the oil groove49 in the lower bearing shell 50. The upper bearing shell 60 has asmooth continuous surface to carry heavier loads of thrust from theconnecting rod 41. It is understood that the passage 47 is incommunication with passage 48, but passage 48 is the outlet passage forthe right bank of the engine through connecting rod 41. Thejpassage 47transmits lubrication fluid to the left bank as shown in FIGS. 2 and 3.

FIG. 3 illustrates the crankshaft rotated to where the passage 48'terminates communication with the oil groove 49 in bearing shell 50. Thecommunication between the passage 43 and the groove 49 in bearing shell50 initiates at 40 before top dead center and terminates at 140 aftertop dead center. It is understood that top dead center refers to topdead center for-the right bank and is illustrated in FIG. 2 with theengine crankshaft 34 at top dead center.

Referring to FIGS. 4 and'5, one of the left bank of cylinders is'illustrated in a cross section as cut in the plane 56 as shown in FIG.9. It is understood that the right bank are illustrated by a crosssection as cut at plane 55 as shown in FIG. 9 and as illustrated inFIGS. 2 and 3.

The connecting rod 59 of the left banks as shown in FIGS. 4 and 5 isessentially rotated at 180 on axis, as compared to the connecting rod 41of the right bank shown in FIGS. 2 and 3. With the.90 V of the enginebanks of cylinders and a 45 diagonal split of'the bearings on thecrankpin end of connecting rod 59, the bolts 61 and 62 extend downwardlyto provide a fastening means for the rod end 63 and the cap end 64 topermit access for repair. f

The cap 160 receives a bearing shell 65 which forms a recess 66. The rodend 161 of crankpin bearing 162 receives the shell 67 with anuninterrupted surface to carry heavy thrust loads.

Passage 47 is in communication with the oil groove 66 of the bearingshell 65 for 180 of rotation since the lower bearing shell forms anoilgroove of 180. The passage 47 initiates communication with the groove66 at 40 before top dead center of the left bank cylinder as shown. Thepassage 47 is in continuous communication for 180 and then isinterrupted by the continuous surface of the bearing shell 67 as thecrankshaft continues to rotate.

A thrust load from the connecting rod 59 is transmitted to the journalportion 38 of the crankshaft 34. The main bearing journaled portion 38includes a lower shell 135 which has a continuous surface to receiveheavy thrust loads from the journaled portion 38. The upper shell 136forms a groove 140 for 180 of arc. With the cross passage 39 extendingdiametrically 5 journaled portion of the crankshaft at the main bearingto carry heavy thrust loads. The initiation and termination ofcommuncation between the main oil gallery supply and the spray orifice12 is controlled by suitable drilling of the crankshaft and grooving ofthe bearing shells for providing heavy thrust loads while stillmaintaining communication between the oil pressure of the main oilgallery to the spray orifice as desired.

Referring to FIG. 10, the graph illustrates lubrication and cooling oilflow in gallons per minute with relation to the engine speed inrevolutions per minute of engines having contrasting oil fiow systems.The line 70 illustrates a negative flow characteristic as engine speedincreases of an engine having main 'oil gallery pressure continuouslyapplied through crankshaft and connecting rod passages which is anunfavorable flow characteristic. As previously indicated the inertiaforces on the oil columns in the crankshaft and connecting rods areallowed to produce this undesirable result.

The line 71 also illustrates a negative flow characteristic of a similarengine with continuous communication between the main oil gallery supplyand the spray orifi'ce 12. Conversely, the line 72 in FIG. 10illustrates a positive flow characteristic foramulti-cylinder engine inwhich an increasing flow in gallons per minute is associated with anincrease in speed of the engine. The flow characteristic shows theresults of proper oil flow control of essentially a rotary valvepositioned in the crankpin bearing of the engine.

FIG. 6 illustrates flow characteristics of an engine with varying groovelengths in the crankpin bearing shell. The initiation of communicationbetween the main gallery oil supply and the spray orifice at the top ofthe wrist pin is 30 before top dead center. The dotdash line 73illustrates oil flow with a groove length of 90. The dotted line 74illustrates oil flow with a groove length of 120, while the solid line75 illustrates oil flow with a groove length of 150.

Referring to FIG. 7, the graph illustrates a similar oil flow chart inwhich communication initiation of the lubricating oil passages betweenthe main oil gallery supply and the spray orifice is initiated at 45before top dead center. The dot-dash line 77 illustrates oil flow with a90 arc of oil groove while the dash line 78 illustrates oil flow with a120 arc of oilgroove and the solid line 79 illustrates oil flow with a150 arc of oil groove. All of the variations in the length of oil groovein the bearing shell illustrates a positive flow characteristic withengine speed. I

Referring to P16. 8, a similar oilflow chart is illustrated. Theinitiation of communication between the main oil gallery supply and thespray orifice is at 60 before top dead center. The dot-dash line 80illustrates the results of oil flow with oil groove arc, while the dashline 31 illustrates oil flow with of oil groove arc, while the solidline 82 illustrates oil flow with of arc in the bearing shell. All ofthe charts illustrate a positive flow characteristic with increase inengine speed. While the various charts illustrate a variation in therate of the oil flow characteristic, it was concluded that asymmetricaltiming for the initiation and termination of oil transmission throughthe connecting rod was necessary. Start of communication was preferrednot to be earlier than 40 before top dead center or later than top deadcenter and continuing for not less than 90 or for more than 180. Byvarying the initiation and termination of communication to provide oilflow though the connecting rod, the desired rate and flowcharacteristics may be achieved. The rotary valve action produced by thecrankpin bearing provides a positive way of improving the flowcharacteristic while simultaneously improving the thrust load which theconnecting rod and crankshaft are able to transmit through the engine.

The operation of this device will be described in the followingparagraphs.

Referring to FIG. 1, the crankshaft 20 is rotatably mounted androtatably connected through the crankpin 19 to the connecting rod 8. Theconnecting rod 8 is connected through the wrist pin 7 to the piston 6.As the crankshaft rotates, the pump 31 supplies pressurized oil to thegroove 30 of the bearing shells 28 and 29 in the main housing 26.Bearing shells 28 and 29 form a continuous groove for the periphery ofthe bearing. The passage 22 extends through the crankarm of thecrankshaft 20 to the crankpin bearing 119. The crankpin bearing isformed with two bearing shells 14 and 16 which form an oil groove 21 atadjacent ends of the bearing shells. The oil groove 21 is incommunication with the diagonal passage 13 in the connecting rod whichextends to the wrist pin bearing 120 and is in communication with theoil groove 10 and bore 11 to spray lubrication and cooling oil on theunderside of the piston 6 through the spray orifice 12. While thecrankshaft 20 is rotating the connecting rod 8 is reciprocating and acolumn of oil in the passage 13 increases and decreases the effectiveoil pressure at the spray orifice 12. During at least a portion of thephase of the cycle while the inertia forces on the oil in the passage 13increase the algebraic sum of all pressures which include the pressureof the main oil gallery, and the pressure produced by the rotationalforce on the oil in the passage 16, communication is provided throughthe rotary valve structure of the crankpin bearing 119. Communication isprovided from the main bearing through the crankpin bearing through thewrist pin bearing to the spray orifice 12. This communication initiates,as shown in FIG. 1, at approximately top dead center. The communicationcontinues for approximately 90 as shown, at which point communication isterminated.

Also illustrated in FIG. 1, provision for extending the oil groovelength in the shells 14 and 16 is shown in the phantom view. In thephantom view of the oil groove initiation of communication is at 45before top dead center and continues for the length of the arc of 180 ofthe oil groove. At this point communication is terminated and for 180 nooil passes through the passage 13. The oil column in passage 13,however, has an inertia effect which will tend to continue to lubricatethe crankpin hearing from the upper side since a negative pressureforcing downwardly will cause some lubrication of the bearings. It isunderstood that the wrist pin bearing 9 has a 360 groove for lubricatingand cooling.

Referring to H08. 2, 3, 4 and 5, the crankshaft shown operates inconjunction with a V-engine. The lubrication system operates similarlyto that shown in FIG. 1; however, initiation and termination oflubrication oil passages as shown in FIG. 9 operate at a different timein the crankshaft rotation. Initiation for each bank of cylinders is at40 before top dead center and continues for 180 of crank rotation andthen terminates. This is illustrated in each of the views shown for theV-engine. The system as shown also provides a cross drilled passage 39in the portion 38 of the crankshaft. This permits smooth continuousbearing surfaces to carry heavier thrust loads'on the main bearing aswell as the crankpin bearing. By supplying lubricating oil continuouslyto the main bearing and through the cross passage 39 and intermittentlythrough the crankpin bearing and 162, initiation and termination of oilflow is controlled in the bearing groove of the crankpin bearing lowershell which does not carry the heavy thrust load. By using the diagonalsplit and favorable positioning of the cylinder banks the bearings andconnecting rods can be readily disassembled when necessary. Similarly,the V-engine provides asymmetrical timing of the lubrication oil flowthrough the crankpin bearing to the spray orifice. The crankpin bearingoperates as a rotary valve to control the flow of lubricating oil tocool the underside of the piston with an increase in cooling with anincrease in speed.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

l. A hydraulic lubricating and cooling system comprising, a crankshaft,at least one main bearing rotatably supporting said crankshaft anddefining an oil groove, a source of pressurized oil supplyingpressurized oil to said main bearing, at least one crankarm having acrankpin on said crankshaft, a connecting rod having a crankpin enddefining a crankpin bearingjournaling said crankpin, said crankpin enddefining an oil groove forming an arcuate segment adjacent said crankpinon the side of said connecting rod, a piston, a wrist pin onnected tosaid piston, a wrist pin end on said connecting rod defining a wrist pinbearing receiving said wrist pin on said piston and forming an oilgroove and an oil orifice for spraying oil on the underside of saidpiston, means defininga passage in said crankarm of said crankshaftintermittently communicating between said source of pressurized oilthrough said main bearing and said oil groove of said crankpin bearingduring a period of asymmetrical timing relation of the crankarm fore andaft of the top dead center position, passage means in said connectingrod for transmitting pressurzed oil from said oil groove in crankpinbearing to said oil groove and said oil orifice in said wrist pinbearing, means in at least one of said bearings defining a rotary valveto provide asymmetrical intermittent flow of pressurized oil from saidmain bearing to said orifice when the inertia forces on the oil in saidpassages of said connecting rod tend to increase oil flow through saidorifice for thereby cooling said piston with a flow rate increasing withengine speed.

2. A hydraulic lubricating and cooling system as set forth in claim 1wherein said connecting rod defines a two partite crankpin bearinghaving a split diagonal to the longitudinal axis of the rod. I

3. A hydraulic lubricating and cooling system as set forth in claim 1wherein said crankpin bearing defines a two partite bearing having asplit normal to the longitudinal axis of said connecting rod.

4. A hydraulic lubricating and cooling system as set forth in claim 1wherein said main bearing defines two bearing shells, means in only oneof said shells defining said oil groove.

5. A hydraulic lubricating and cooling system as set forth in claim llwherein said main bearing defines said oil groove extending for anarcuate segment of the periphery of said main bearing.

6. A hydraulic lubricating and cooling system as set forth in claim l.wherein said crankpin bearing defines a continuous surface on theportion of the bearing surface carrying the gas thrust load.

7. A hydraulic lubricating and cooling system as set forth in claim llwherein said crankpin bearing defines said oil groove for an arcuatesegment of the periphery of said crankpin bearing for for the periof ofasymmetrical timing of communication between said main bearing and wristpin bearing for a substantially greater degree of crank rotation aftertop dead center than before.

8. A hydraulic lubricating and cooling system as set forth in claim llwherein said main bearing defines two bearing shells, said main bearingdefines said oil groove for an arcuate segment for the full 180 of oneof said bearing shells, said passage means in said crankshaft defines adiametric hole in communication with said crankpin bearing to therebyprovide continual communication from said main bearing to said crankpinbear- 9. A hydraulic lubricating and cooling system as set forth inclaim 1 wherein said means in at least one of said bearings defines saidrotary valve initiating communication between said main bearing and saidorifice approximately 40 before top dead center.

10. A hydraulic lubricating and cooling system as set forth in claim 1wherein said means in at least one of said bearings defines said rotaryvalve initiating communication between said main bearing and saidorifice at approximately top dead center.

11. A hydraulic lubricating and cooling system as set forth in claim 1wherein said oil groove in said crankpin bearing defines an arc ofapproximately 90 to provide communication between said main bearing andsaid orifice for approximately 90 of crankshaft rotation.

12. A hydraulic lubricating and cooling system as set forth in claim llwherein said oil groove in said crankpin bearing defines an arc ofapproximately l to provide communication between said main bearing andsaid orifice for approximately l80 of crankshaft rotation.

13. A hydraulic lubricating and cooling system as set forth in claim Rwherein said oil groove in said main bearing defines an arcuate groovefor the full 360 to provide continuous communication between said mainbearing and said crankpin bearing.

14. A hydraulic lubricating and cooling system as set forth in claim 1wherein said crankpin bearing includes two connecting rods, a firstconnecting rod for operating in the left bank of a V-engine, a secondconnecting rod for operating in the right bank of a V-engine, saidpassage means in said crankshaft defining passages for connecting saidmain bearing to said first and said second connecting rods in saidcrankpin bearing.

15. A hydraulic lubricating and cooling system as set forth in claim 1wherein said passage means in said connecting rod defines a diagonalpassage diagonal to the center line of said rod, said crankpin bearingdefines said oil groove for an arcuate segment on one side of saidcrankpin bearing of said rod in communication with said diagonalpassage, said rod defining said diagonal passage connecting said oilgroove on the opposite side of said wrist pin bearing of said rod tothereby provide communication between said wrist pin bearing and saidcrankpin bearing.

16. A hydraulic lubricating andcooling system as set forth in claim 1wherein said crankpin bearing includes two connecting rods, a firstconnecting rod adapted for operating in the left bank of a V-engine, asecond connecting rod adapted for operating in a right bank of aV-engine at relative to the said first connecting rod, each of saidconnecting rods defining a crankpin two partite bearings defining a slitat at 45 angle with the longitudinal axis of its mating connecting rodand substantially in a horizontal plane.

l l =l= l

1. A hydraulic lubricating and cooling system comprising, a crankshaft,at least one main bearing rotatably supporting said crankshaft anddefining an oil groove, a source of pressurized oil supplyingpressurized oil to said main bearing, at least one crankarm having acrankpin on said crankshaft, a connecting rod having a crankpin enddefining a crankpin bearing journaling said crankpin, said crankpin enddefining an oil groove forming an arcuate segment adjacent said crankpinon the side of said connecting rod, a piston, a wrist pin connected tosaid piston, a wrist pin end on said connecting rod defining a wrist pinbearing receiving said wrist pin on said piston and forming an oilgroove and an oil orifice for spraying oil on the underside of saidpiston, means defining a passage in said crankarm of said crankshaftintermittently communicating between said source of pressurized oilthrough said maiN bearing and said oil groove of said crankpin bearingduring a period of asymmetrical timing relation of the crankarm fore andaft of the top dead center position, passage means in said connectingrod for transmitting pressurized oil from said oil groove in crankpinbearing to said oil groove and said oil orifice in said wrist pinbearing, means in at least one of said bearings defining a rotary valveto provide asymmetrical intermittent flow of pressurized oil from saidmain bearing to said orifice when the inertia forces on the oil in saidpassages of said connecting rod tend to increase oil flow through saidorifice for thereby cooling said piston with a flow rate increasing withengine speed.
 2. A hydraulic lubricating and cooling system as set forthin claim 1 wherein said connecting rod defines a two partite crankpinbearing having a split diagonal to the longitudinal axis of the rod. 3.A hydraulic lubricating and cooling system as set forth in claim 1wherein said crankpin bearing defines a two partite bearing having asplit normal to the longitudinal axis of said connecting rod.
 4. Ahydraulic lubricating and cooling system as set forth in claim 1 whereinsaid main bearing defines two bearing shells, means in only one of saidshells defining said oil groove.
 5. A hydraulic lubricating and coolingsystem as set forth in claim 1 wherein said main bearing defines saidoil groove extending for an arcuate segment of the periphery of saidmain bearing.
 6. A hydraulic lubricating and cooling system as set forthin claim 1 wherein said crankpin bearing defines a continuous surface onthe portion of the bearing surface carrying the gas thrust load.
 7. Ahydraulic lubricating and cooling system as set forth in claim 1 whereinsaid crankpin bearing defines said oil groove for an arcuate segment ofthe periphery of said crankpin bearing for for the period ofasymmetrical timing of communication between said main bearing and wristpin bearing for a substantially greater degree of crank rotation aftertop dead center than before.
 8. A hydraulic lubricating and coolingsystem as set forth in claim 1 wherein said main bearing defines twobearing shells, said main bearing defines said oil groove for an arcuatesegment for the full 180* of one of said bearing shells, said passagemeans in said crankshaft defines a diametric hole in communication withsaid crankpin bearing to thereby provide continual communication fromsaid main bearing to said crankpin bearing.
 9. A hydraulic lubricatingand cooling system as set forth in claim 1 wherein said means in atleast one of said bearings defines said rotary valve initiatingcommunication between said main bearing and said orifice approximately40* before top dead center.
 10. A hydraulic lubricating and coolingsystem as set forth in claim 1 wherein said means in at least one ofsaid bearings defines said rotary valve initiating communication betweensaid main bearing and said orifice at approximately top dead center. 11.A hydraulic lubricating and cooling system as set forth in claim 1wherein said oil groove in said crankpin bearing defines an arc ofapproximately 90* to provide communication between said main bearing andsaid orifice for approximately 90* of crankshaft rotation.
 12. Ahydraulic lubricating and cooling system as set forth in claim 1 whereinsaid oil groove in said crankpin bearing defines an arc of approximately180* to provide communication between said main bearing and said orificefor approximately 180* of crankshaft rotation.
 13. A hydrauliclubricating and cooling system as set forth in claim 1 wherein said oilgroove in said main bearing defines an arcuate groove for the full 360*to provide continuous communication between said main bearing and saidcrankpin bearing.
 14. A hydraulic lubricating and cooling system as setforth in claim 1 wherein said crankpin bearing includes two connectingrods, a fIrst connecting rod for operating in the left bank of aV-engine, a second connecting rod for operating in the right bank of aV-engine, said passage means in said crankshaft defining passages forconnecting said main bearing to said first and said second connectingrods in said crankpin bearing.
 15. A hydraulic lubricating and coolingsystem as set forth in claim 1 wherein said passage means in saidconnecting rod defines a diagonal passage diagonal to the center line ofsaid rod, said crankpin bearing defines said oil groove for an arcuatesegment on one side of said crankpin bearing of said rod incommunication with said diagonal passage, said rod defining saiddiagonal passage connecting said oil groove on the opposite side of saidwrist pin bearing of said rod to thereby provide communication betweensaid wrist pin bearing and said crankpin bearing.
 16. A hydrauliclubricating and cooling system as set forth in claim 1 wherein saidcrankpin bearing includes two connecting rods, a first connecting rodadapted for operating in the left bank of a V-engine, a secondconnecting rod adapted for operating in a right bank of a V-engine at90* relative to the said first connecting rod, each of said connectingrods defining a crankpin two partite bearings defining a slit at a 45*angle with the longitudinal axis of its mating connecting rod andsubstantially in a horizontal plane.